Description
C Typedef is nothing but "Type-Definition".
C Typedef is used to give alternative names to the original names to reduce the complexity of the program. They acts as "alias names" or "shorthand versions" of structure names/data-types.
Syntax
typedef original_name alternate_name;
Eg:
typedef int number;
number x=10; //number really means int Example
[c]#include<stdio.h>
#include<string.h>
#include<limits.h>
int main()
{
typedef long long int lli;
printf("Storage size for lli type: %ld", sizeof(lli));
return 0;
}[/c]
Output:
[c]Storage size for lli type: 8[/c]
Advantages
- Checking for bugs becomes easier.
- type-def reduces the memory size also.
- User finds no complexity in writing the program.
- Simplification of the commands can be done as per the need.
- It deals with platform independent issues.
Description
To declare a name to which already C typedef exists, that name should consists of a type-specifier to avoid confusion. If want to use typedef with function, specify only the return value not all the parameters of the function.
Example
[c]
#include <stdio.h>
#include <string.h>
typedef struct student
{
int id;
char name[20];
float percentage;
} status;
int main()
{
status record;
record.id=1;
strcpy(record.name, "James");
record.percentage = 86.5;
printf(" Id is: %d \n", record.id);
printf(" Name is: %s \n", record.name);
printf(" Percentage is: %f \n", record.percentage);
return 0;
}[/c]
Output:
[c]
Id is: 1
Name is: James
Percentage is: 86.500000
[/c]
Key Points
- C Typedef gives user-defined data types.
- All data types defined will be under the control of compiler.
Programming
Tips
Declarations must be clear to avoid confusion between two alias names.